In the field of vehicle, the structural design of engine compartments of vehicle is very important to safety performance of collision. The vehicle engine compartment must be stable and capable of absorbing energy efficiently, when it is collided from different angles or with different overlapping rates. The results of IIHS (Insurance Institute for Highway Safety) small overlap crashtests in recent two years show that, most of cars have poor performance in collision when they are collided from different angles or with different overlapping rates. With the rise of competition, vehicle parts are expected to be interchangeable between different vehicle models. However, for the same engine compartment structure, when it is used in different vehicle models, particularly in vehicle models with different size and weight, there will be a big difference with respect to the collision performance. Therefore, on the premise of maintaining the universality of vehicle parts for engine compartment, how to ensure the collision performance of vehicle, even in IIHS small overlap crashtests, is a large challenge in vehicle structural design.
FIG. 1 is a schematic view showing a traditional engine compartment. As shown in FIG. 1, the engine compartment includes a front bumper 1, an upper longitudinal beam 2, a front subframe 3 and an A-pillar 4. The front bumper 1, the upper longitudinal beam 2 and the front subframe 3 cooperatively form a “” shaped structure. Rear portions of the upper longitudinal beam 2 and the front subframe 3 are connected to upper and lower portions of the A-pillar 4 to form a “” shaped structure. The engine compartment has an arc-shaped front longitudinal beam structure connected in large overlapping area with a passenger compartment, which can deform to absorb energy and has stable crumple modes and excellent crashworthiness when subject to head-on collision. However, the engine compartment has disadvantages listed hereinafter.
1. Insufficiency in absorbing energy. The engine compartment has only two load transfer paths, with one load transfer path from the front bumper to the upper longitudinal beam and then to the A-pillar, and the other load transfer path from the front bumper to the front subframe and then to the A-pillar. Thus, the energy absorption requirement for each load transfer path is high, and the structural parts in each load transfer path generally adopt large cross-section or large thickness to meet the energy absorption requirement.
2. Bad performance in crashworthiness collided from different angles. Because the engine compartment has only two load transfer paths, in a side view of the vehicle (i.e., seen from a direction of the width of the vehicle), a distance between the upper longitudinal beam and the subframe cannot be too large to ensure a rigidity and a stability of the engine compartment.